Pegomya prisca, Michelsen, Verner, 2006

Michelsen, Verner, 2006, A new European species of Pegomya Robineau­Desvoidy (Diptera: Anthomyiidae) near P. t e s t a c e a (De Geer), Zootaxa 1260, pp. 37-46 : 38-39

The Pegomya testacea species group

In this newly established species group confined to the Palaearctic Region, I recognize the following taxa: P. t e s t a c e a (De Geer), P. h a m a t a Wei and P. prisca sp. nov. described below.

Pegomya testacea (De Geer) is better known in the literature under the junior synonym P. s i l a c e a (Meigen), see Persson et al. (1984) for details, and the species was inadvertently listed under both names in the ‘Catalogue of Palaearctic Diptera’ (Dely­ Draskovits 1993). Pegomya testacea ranges west–east from the British Isles to the highland border zone between Israel, Lebanon and Syria and north–south from southern Finland to Morocco and Crete.

Pegomya hamata Wei , a species described in Wei et al. (1999) on the basis of a single male from China, Guizhou Province, was compared to P. testacea from which it differs mainly by the darkish thorax and antennal postpedicel. In that respect it is reminiscent of P. p r i s c a. However, the illustrations given of the male terminalia of the Chinese taxon suggest that it is different from both P. p r i s c a and P. t e s t a c e a, especially as regards the structure of the distiphallus and gonites. Pegomya hamata hardly differs from P. prisca in respect to sternite V whereas the subangular caudal outline of the epandrium is in good agreement with P. testacea .

Description. The following combination of characters should enable recognition of males and females of the P. t e s t a c e a species group from other species of Pegomya :

Large­sized, wing length 6.0– 8.6 mm. Colour: Head, body and legs predominantly or wholly yellow to yellowish brown. Basal antennal articles, haustellum and palpus entirely yellow. Setae on ventral part of head all dark coloured. Head: Strongly holoptic in male; combined width of narrow, contiguous fronto­orbital plates less than diameter of anterior ocellus. Female with a broad frons, a pair of well developed interfrontal setae, and three pairs of orbital setae. Genal setae arranged in single row. Thorax: Rows of strong acrostichal setae more widely separated from each other than from dorsocentral setal rows; prealar seta long, same length as anterior notopleural seta. Wings: Vein C setulose dorsally except almost bare in male P. testacea . Lower calypter a little larger than upper calypter, thus distinctly projecting behind upper calypter, especially in male. Legs: Hind tibia with 3 ad and 2 pd setae.

Male abdomen: Rather short, depressed, only slightly thickened caudally; tergite VI bare. Lobes of sternite V ( Figs. 1 , 8 ) with one strong seta apically and two strong setae subbasally. Surstyli ( Figs. 2 , 9 ) with ‘apical’ incision moved subbasally and dividing each surstylus into a short inner lobe and a long, arched outer lobe, the latter with two laminate ridges on inner surface. Cerci ( Figs. 2–3 , 9–10 ) broad­based, forming a prominent, tapering apex. External part of phallapodeme ( Fig. 4 ) distally strongly tapering. Pregonite ( Figs. 5 , 11 ) broad, with 0?–1 seta on anterior lobe and 2 setae on top of slender, posterior lobe; postgonite ( Figs. 6 , 12 ) with a thick, apically cleft seta subbasally. Distiphallus ( Figs. 7 , 13 ) club­shaped, with discrete acrophallus and paraphallic processes.

Female abdomen: Oviscapt ( Figs. 14–15 , 16–17 ) medium­long, slender; tergite and sternite VIII each with a single row of erect hind marginal setae; epiproct obtuse, with some apical setae; hypoproct large, abundantly pubescent and setose; freely projecting apex of cerci long, cylindrical, abundantly setose with one very long seta apically.

Figures

FIGURES 1 – 7. Pegomya prisca sp. nov., male terminalia. 1. Sternite V. 2. Hypopygium, caudal. 3. Hypopygium, lateral. 4. Phallapodeme. 5. Pregonite. 6. Postgonite. 7. Phallus. Scale = 0.25 mm.

FIGURES 8 – 13. Pegomya testacea (De Geer), male terminalia. 8. Sternite V. 9. Hypopygium, caudal. 10. Hypopygium, lateral. 11. Pregonite. 12. Postgonite. 13. Phallus. Scale = 0.25 mm.

FIGURES 14 – 15. Pegomya spp., oviscapt, flat mounted. 14. P. p r i s c a sp. nov. 15. P. testacea (De Geer). Scale = 0.5 mm.

FIGURES 16 – 17. Pegomya spp., distal part of oviscapt, flat mounted. 14. P. p r i s c a sp. nov. 15. P. testacea (De Geer). Scale = 0.25 mm.